How to Merge two XMLs in Java

I have a solution that works for me. Now experts, please advise if this is the way to go.

Thanks, -Nilesh

    XMLEventWriter eventWriter;
    XMLEventFactory eventFactory;
    XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
    XMLInputFactory inputFactory = XMLInputFactory.newInstance();
    eventWriter = outputFactory.createXMLEventWriter(new FileOutputStream("testMerge1.xml"));
    eventFactory = XMLEventFactory.newInstance();
    XMLEvent newLine = eventFactory.createDTD("\n");                
    // Create and write Start Tag
    StartDocument startDocument = eventFactory.createStartDocument();
    eventWriter.add(startDocument);
    eventWriter.add(newLine);
    StartElement configStartElement = eventFactory.createStartElement("","","TestCaseBlock");
    eventWriter.add(configStartElement);
    eventWriter.add(newLine);
    String[] filenames = new String[]{"test1.xml", "test2.xml","test3.xml"};
    for(String filename:filenames){
           XMLEventReader test = inputFactory.createXMLEventReader(filename,
                             new FileInputStream(filename));
        while(test.hasNext()){
            XMLEvent event= test.nextEvent();
        //avoiding start(<?xml version="1.0"?>) and end of the documents;
        if (event.getEventType()!= XMLEvent.START_DOCUMENT && event.getEventType() != XMLEvent.END_DOCUMENT)
                eventWriter.add(event);         
        eventWriter.add(newLine);
            test.close();
        }           
    eventWriter.add(eventFactory.createEndElement("", "", "TestCaseBlock"));
    eventWriter.add(newLine);
    eventWriter.add(eventFactory.createEndDocument());
    eventWriter.close();

General solution still would be XSLT, but you'd need to combine two files into one big XML first with a wrapper element (XSLT works with one input source).

<root>
    <TestCaseBlock>
        <TestCase TestCaseID="1">
        ...
        </TestCase>
    </TestCaseBlock>
    <TestCaseBlock>
        <TestCase TestCaseID="2">
        ...
        </TestCase>
    </TestCaseBlock>
</root>

Then just do XSLT for match="//TestCase", and dump all test cases out, ignoring what test case block they belong to.

And don't worry about performance until you have tried. XML APIs in JAva are getting much better than in 2003.

This is stylesheet you need:

<?xml version="1.0" encoding="ISO-8859-1"?>

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

    <xsl:output method="xml" encoding="UTF-8" indent="yes"/>

    <xsl:template match="/">
            <TestCaseBlock>
                <xsl:apply-templates/>
            </TestCaseBlock>
    </xsl:template>

    <xsl:template match="//TestCase">
          <xsl:copy-of select="."/> 
    </xsl:template>

</xsl:stylesheet>

Tested, it works.

BTW, this XSLT was compiled and executed on this (small) example in 1ms.